Humans & Society

Topic Image Rail

PRETTY PLANET One Strange Rock contains gorgeous images of Earth, such as these colorful hydrothermal fields in Dallol, Ethiopia.

Graham Booth/National Geographic

ARCTIC BLAST A new study finds a strong correlation between Arctic warming and heavy snowfall in the northeastern United States, such as this March 13 storm that struck Boston.

Lisa Grossman

TOOLING DOWN By around 320,000 years ago in East Africa, Homo sapiens or a close relative had shifted from making large chopping implements (left) to fashioning spearpoints and other small tools (right).